Black Rocks Surf Stats

The rose diagram shows the combination of swells directed at Black Rocks over a normal July and is based upon 3720 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the most applicable grid node based on what we know about Black Rocks. In the case of Black Rocks, the best grid node is 43 km away (27 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 35% of the time. Green and yellow show increasing swell sizes and red shows the biggest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the prevailing swell direction, shown by the largest spokes, was SSW, whereas the the prevailing wind blows from the ESE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Black Rocks and away from the coast. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Black Rocks, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical July, swells large enough to cause clean enough to surf waves at Black Rocks run for about 65% of the time.

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